Liquid pretreatment of an image bearing surface to increase absorbency of nonimage area



United States Patent O LIQUID PRE'I'REAI'MENT OF AN IMAGE BEAR- ING SURFACE TO INCREASE ABSORBENCY F NONIMAGE AREA Frederick J. Stryker, San Jose, and Frederik M. Verduyn, Palo Alto, Calif., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Army No Drawing. Filed Mar. 26, '1968, Ser. No. 716,237

Int. Cl. B41m 5/02; B44d 7/04 U.S. Cl. 117--1.7 6 Claims ABSTRACT OF THE DISCLOSURE A process for enhancing the quality of an image which has been produced by the Reduced Layer Formation (RLF) process, comprising the pretreatment of an image bearing original with a material so as to increase the absorption of an oil in the nonimage area.

This invention relates to an improvement for the reproduction of a latent oil image of an original document onto a copy paper and more specifically to an improvement comprising the pretreatment of an image bearing original with a material so as to increase the absorption of a liquid in the nonimage area thereby enhancing the quality of the transferred image.

The RLF process developed by Abrams Games, which is the subject of Dutch patent application 6415234, is one of the methods utilized to reproduce original designs such as letters, printed and duplicated matter, photographs, drawings or other specially prepared originals whether on paper or other surfaces. The RLF process is based on the discovery that the production of an original design may decrease the absorbency of the surface to liquids in the image area defining the design and that of the resultant diiferential absorbency as between the image and nonimage areas can be utilized in the production of copies.

The range of liquids which can be diiferentially absorbed in the RLF process depend on the nature of the surface and of the image. In general, the liquids utilized are colorless so as not to perceptibly mark the original, have little or no odor and are nontoxic. Suitable liquids include, for example, water, milk, diethylene glycol, monethyl ether, glyceryl triacetate, glycerine, diethyl and dimethyl phthalates, and dilute benzoic acid.

One method in accordance with the RLF process comprises positioning a layer of a suitable liquid between the design bearing surface of the original and a second surface in contact with the original. The eifect of the differential absorption is that the layer of liquid is formed into a pattern corresponding to the original design and when the second surface is removed, it carries with it a liquid pattern defining a mirror image of the original design.

The RLF process is based on the discovery that the production of an original design may decrease the absorbency of the surface to liquids in the image areas defining the design and that the resultant differential absorbency as between the image and nonimage areas can be utilized in the production of copies. The differential absorbency may arise from the nature of material added in the image areas, e.g., by printing or by the application of inks or pigments, or it may be inherent in the original itself, as in the case of photographs. Some originals which do not exhibit this difierential absorbency can be given a pretreatment so as to render them suitable.

In copending application 716,236 filed Mar. 26, 1968 ice by Frederick J. Stryker and Otto Kornei there is described an improved method for the chemical reproduction of latent oil image reproduced by the RLF process. In 00- pending application 716,236, filed Mar. 26, 1968 by Frederick J. Stryker, sole, there is described the utilization of oleic acid as a suitable liquid for the reproduction of a latent oil image by the -RLF process. The present invention relates to pretreatment of an image containing original which does not exhibit ditferential absorbency in order to impart thereto difierential absorbency as between the image and nonimage area. The pretreated image bearing original may then be subjected to the RLF process to reproduce the image onto a copy paper.

It is an object of this invention to provide and disclose a process for pretreating an image bearing original in order to impart thereto diiferential absorbency as between the image and nonimage areas.

Other objects and a fuller understanding of the invention may be ascertained from the following description and claims.

An essential requirement for the operability of the RLF process is that there must be a differential absorption of liquid between the image and nonimage areas of the original to be reproduced. However, if the original does not possess these differential absorption characteristics, or if the differential absorption of a liquid between the image and nonimage areas of the original to be reproduced is slight, said differential absorption characteristic may be improved by pretreatment of the original. Primarily the pretreatment increases the absorption of the oil in the nonimage areas. Set forth below are examples of the pretreatment solutions comprising ingredients and amounts thereof:

EXAMPLE 1 Gms. Wetting agent 10 Glycerol 10 Alcohol 10 Polytergent G 200 was utilized as a wettingagent (Olin Mathieson Chemical Corporation).

EXAMPLE 2 Carbowax, mol wt. 400.

Polyethylene glycol, trademark of Union Carbide Corp.

The polyethylene glycol utilized may have molecular weights of 400, 500, 1000, 1500, 4000 and 6000. In addition, the polyethylene glycol may be dissolved in water 10-50% solution) and E. I. du Pont de Nemours & Co. Duponol W-144 (a surface-active agent of the alcohol sulfate type) added, for example,

Carbowax 550 Water EXAMPLE 3 Gms. Polytergent B-lSO 15 Isopropanol The Polytergent Bl50 wetting agent (Olin Mathieson Chemical Corporation) may be utilized in an amount of 520% by weight.

EXAMPLE 4 Gms. 15 85 Oleic acid Alcohol The oleic acid may be utilized in amounts -40% by weight. Any alkyl alcohol having 1-3 carbon atoms or a mixture thereof may be used EXAMPLE 5 Gms.

Gallic acid 5 Alcohol 95 In the alternative, a small amount of a surface-active agent, e.g., 6 drops of Duponol L-144, may be added to each four ounces of the above solution. The gallic acid may be utilized in the solution in an amount of 2-5%. The alcohol may be anyv alkyl alcohol having 1-3 carbon atoms or a mixture thereof. I

The pretreatment solution may be applied to the image bearing original by any conventional manner, for example, spraying or by means of a roller. The amount of solutioniutilized to treat the image bearing original is not critical to the operability of the process in that only an amount sufiicient to wet the material to be treated is required.

Although we have described our invention with a certain degree of particularity, it is understood that the foregoing is made to set forth the best mode contemplated in carrying out the invention and not as a limitation thereof, in that many modifications may be made in the combination of proportions, for example, without the vitiation of the operability of the invention.

Having described our invention, we claim:

1. In a process for the reproduction of a latent oil image from an original onto a second surface comprising; the application of a transferable image forming liquid to the surface of the original having a differential absorbency as between the image and nonimage areas thereby forming a liquid pattern corresponding to the image, contacting the original with the second surface whereby a layer of the liquid pattern corresponding to the original image is transferred to the second surface, and rendering the transferred image visible: the improvement wherein the image bearing original is pretreated with a liquid prior to the contacting thereof with the image forming liquid in order to increase the absorbency of the nonimage area, and the pretreating liquid is:

(l) a mixture of 50-90 percent polyethylene glycol having a molecular weight of 400 to 6000, and 10-50 percent Water,

(2) a mixture of 2-5 percent gallic acid, and 95 to 98 percent of an alkyl alcohol having 1-3 carbon atoms, or an alcohol component comprising a mixture of alkyl alcohols having 1-3 carbon atoms, or

(3) a mixture of 5-40 percent oleic acid, and 60-95 percent of an alkyl alcohol having l-3 carbon atoms, or an alcohol component comprising a mixture of alkyl alcohols having 1-3 carbon atoms,

all proportions being on a part by weight basis.

2. A process in accordance with claim 1 wherein the pretreating liquid comprises a mixture of -90 percent polyethylene glycol having a molecular weight of 400 to about 6000, and 10-50 percent water.

3. A process in accordance with claim 1 wherein the pretreating liquid comprises a mixture of 2-5 percent gallic acid, and 95-98 percent of an alkyl alcohol having 1-3 carbon atoms.

4. A process in accordance with claim 1 wherein the pretreating liquid comprises a mixture of 2-5 percent gallic acid, and 95-98 percent of a mixture of alkyl alcohols having 1-3 carbon atoms.

5. A process in accordance with claim 1 wherein the pretreating liquid comprises a mixture of 5-40 percent oleic acid, -95 percent of an alkyl alcohol having 1-3 carbon atoms.

6. A process in accordance with claim 1 wherein the pretreating liquid comprises a mixture of 5-40 percent oleic acid, and 60-95 percent of a mixture of alkyl alcohols having 1-3 carbon atoms.

FOREIGN PATENTS 1,091,501 11/1967 Great Britain.

OTHER REFERENCES Chemical and Engineering News, Jan. 29, 1968, p. 24.

WILLIAM D. MARTIN, Primary Examiner E. J. CABIC, Assistant Examiner US. Cl. X.R. 1 17-37 

